Patent GB-746595-A (GB)
Title: Improvements in and relating to double pipe heat exchangers
Inventor: GOURLAY ROBERT
IPC: F28F19/00
Filed: 1953-01-15
Abstract: 746,595. Clearing double pipe heat exchangers. CRAIG & CO., Ltd., A. F. Jan. 6, 1954 [Jan. 15, 1953], No. 1225/53. Class 99(2). In a double pipe heat exchanger consisting of a series of interconnected inner pipes each enclosed by an outer pipe or jacket through each of which extends an axial shaft carrying scrapers which bear on the inner faces of the inner pipes, the shafts are supported by a series of bearings each comprising a hub through which a scraper carrying shaft passes, radial arms extending from the hub and arcuate feet carried by the arms, the ends of the feet being of wedge formation, and a series of stops one for each bearing projecting inwardly from the inner pipe. a stop contacting with a side of one of the feet of each bearing, the stops preventing rotation of the bearings but permitting withdrawal of the shafts together with the bearings and the wedge formation of the feet enabling the feet to be drawn and pushed past the stops when the shafts are being withdrawn and reinserted in the inner pipes. The application to removing paraffin wax from wax bearing distillates is referred to. The heat exchanger comprises a plurality of pairs of double pipes. The double pipes form a series of tiers each formed of two double pipes which lie at a slight inclination to the horizontal. The liquid is introduced to one of the lowermost pipes flows through this pipe to a transverse bend d by which it is delivered to the second pipe of the lowermost tier. The liquid passes through this lowermost pipe and at its end is introduced into a vertical header c which conducts it to one of the pipes of the second tier. It flows through this pipe and at the other end is conducted by a transverse header d to the other pipe forming the second tier. In like manner the flow is continued throughout all the pipes of the apparatus. Thus the distillate which is introduced to one of the lowermost pipes flows in zig-zag manner through each inner pipe in turn and passes to a discharge pipe connected to one of the uppermost inner pipes. The outer pipes b form with the inner pipes annular spaces e each of which at one end is connected by means of a branch duct f with a common header. Refrigerant or cooling agent flows from the header through the ducts to the annular spaces. Discharge is through branch ducts f<SP>1</SP> to a header and vapour accumulator. Extending into each inner pipe a is a shaft y formed of a series of interconnected lengths. The shafts are driven in unison by a chain and sprocket drive the chains being driven by a motor the chains and motor not being shown. Each shaft is rotatably supported by means of a series of non-rotatable bearings i each comprising a hub or boss with a bush k. Stops o in the form of pins are carried by the inner pipes a and abut against one of the feet m of each bearing and thereby prevent rotation of the bearings. Springs s urge scrapers p against the inner surfaces of the pipes. The scrapers remove wax deposited on the inner faces of the pipes. The ends of the feet m are of wedge formation.